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Chinese Journal of Catalysis
2012, Vol. 33, No. 4
Online: 13 April 2012


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Dr. Li, Dr. Nakagawa, and Prof. Tomishige in their review on pages 583–594 describe the modification of Ni catalysts for the conversion of biomass tar to synthesis gas. Modification with CeO₂ affords high activity and coke resistance by the formation of Ni-CeO₂ nanocomposite. Modification with Pt gives the ability of self-activation, resulting in a Pt-Ni alloy. The self-regeneration property is attached to the catalyst by further modification with MgO via the formation and reduction of the NiO-MgO solid solution. These ideas will be helpful for designing new multi-functional catalysts for biomass gasification to synthesis gas.

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Table of Contents for Vol. 33 No. 4 2012, 33 (4):  0-0.  Abstract ( 978 )   PDF (1557KB) ( 863 )

Summary

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Development of Ni-Based Catalysts for Steam Reforming of Tar Derived from Biomass Pyrolysis Dalin LI, Yoshinao NAKAGAWA, Keiichi TOMISHIGE 2012, 33 (4):  583-594.  DOI: 10.1016/S1872-2067(11)60359-8 Abstract ( 3043 )   [Full Text(HTML)] () PDF (998KB) ( 1755 )   Nickel catalysts are effective for the steam reforming of tar derived from biomass pyrolysis, but the improvement is needed in terms of activity, stability, suppression of coke deposition and aggregation, and regeneration. Our recent development of Ni-based catalysts for the steam reforming of tar is reviewed including the modification with CeO2 (or MnO), trace Pt, and MgO. The role of additives such as CeO2, MnO, Pt, and MgO is also discussed.

Research Briefing

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Catalysis by Lead Oxide for Diethyl Carbonate Synthesis from Ethyl Carbamate and Ethanol GUO Lian, ZHAO Xin-Qiang, AN Hua-Liang, WANG Yan-Ji 2012, 33 (4):  595-600.  DOI: 10.1016/S1872-2067(11)60373-2 Abstract ( 2926 )   [Full Text(HTML)] () PDF (483KB) ( 855 )   The catalysis by lead oxide in the reaction of ethyl carbamate (EC) with ethanol to form diethyl carbonate (DEC) was studied. The lead oxide catalyst exhibited an excellent stability, which could be reused five times without a significant loss in catalytic activity. X-Ray powder diffraction analysis showed that the recovered catalyst was a mixture of cubic metal Pb and orthorhombic PbO2, with the latter shown to be the real active component for the synthesis of DEC. Verification experiments showed that the reaction between DEC and PbO was the main reason for the reduction of PbO to metal Pb.

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Transesterification of Phenol and Dimethyl Carbonate Catalyzed by Titanium Oxide Acetylacetonate Catalyst LI Bi-Jing, TANG Rong-Zhi, CHEN Tong, WANG Gong-Ying 2012, 33 (4):  601-604.  DOI: 10.1016/S1872-2067(11)60381-1 Abstract ( 2859 )   [Full Text(HTML)] () PDF (436KB) ( 930 )   Titanium oxide acetylacetonate (TiO(acac)2) was found to be a novel and efficient heterogeneous catalyst for the transesterification of phenol and dimethyl carbonate (DMC) to diphenyl carbonate (DPC). The conversion of phenol was 45.8% on the TiO(acac)2 pretreated at 180 oC, and the turnover number reached 96, which was better than the more common organic titanium catalyst. The effect of the amount of catalyst on the catalytic performance was investigated. The transesterification selectivity decreased with catalyst loadings over 0.2 g per 100 ml reactants. At the optimized amount of catalyst the conversion of phenol was 42.4%, and no anisole was detected. In particular, the TiO(acac)2 catalyst proved reusable, and catalytic activity of the recovered TiO(acac)2 was almost the same as that of the fresh catalyst. The conversion of phenol 40.0% was attained from TiO(acac)2 recovered for the fifth time.

Research papers

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Hydrogenation of 2,2,6,6-Tetramethylpiperidin-4-one over Cu30Cr5/Basic Alumina MA Jian-Chao, LIU Shuai, FAN Xiao-Peng, DU Xiao-Bao, YAN Xi-Long, CHEN Li-Gong 2012, 33 (4):  605-609.  DOI: 10.1016/S1872-2067(11)60341-0 Abstract ( 2918 )   [Full Text(HTML)] () PDF (491KB) ( 802 )   Alumina B (basic alumina, pH > 8) was used as the support of copper-chromium catalysts for continuous hydrogenation of 2,2,6,6-tetramethylpiperidin-4-one (TAA) to 2,2,6,6-tetramethylpiperidin-4-ol (TMP). It was found that Cu30Cr5/alumina B exhibited better catalytic performance than Cu30Cr5/γ-Al2O3. 99.0% conversion of TAA and 97.2% selectivity for TMP were obtained over Cu30Cr5/alumina B under optimized conditions. Cu30Cr5/γ-Al2O3 and Cu30Cr5/alumina B were characterized by N2 adsorption-desorption, X-ray diffraction, X-ray photoelectron spectroscopy, and NH3 temperature-programmed desorption. The results showed that Cu particles dispersed better in Cu30Cr5/alumina B than in Cu30Cr5/γ-Al2O3.

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Selective Hydrogenation of Benzene to Cyclohexene over a Ru-Zn Catalyst with Diethanolamine as an Additive SUN Hai-Jie, PAN Ya-Jie, WANG Hong-Xia, DONG Ying-Ying, LIU Zhong-Yi, LIU Shou-Chang 2012, 33 (4):  610-620.  DOI: 10.1016/S1872-2067(11)60351-3 Abstract ( 3340 )   [Full Text(HTML)] () PDF (1041KB) ( 814 )   A Ru-Zn catalyst was prepared by co-precipitation, and the effect of adding diethanolamine on benzene selective hydrogenation to cyclohexene was investigated. The catalyst was characterized by N2 physisorption, transmission electron microscopy, X-ray diffraction, X-ray fluorescence, Fourier transform infrared spectra, and temperature-programmed reduction. Diethanolamine reacted with ZnSO4 in the slurry to form (Zn(OH)2)3(ZnSO4)(H2O)3 and diethanolamine sulfate. The amount of (Zn(OH)2)3(ZnSO4)(H2O)3 adsorbed on the catalyst surface increased with the increase of diethanolamine amount. The synergism of (Zn(OH)2)3(ZnSO4)(H2O)3 and diethanolamine sulfate improved the cyclohexene selectivity of the Ru-Zn(4.9%) catalyst. With a diethanolamine dosage of 0.3 g, (Zn(OH)2)3(ZnSO4)(H2O)3 was highly dispersed on the catalyst surface and the sample after hydrogenation was characterized, and this catalyst exhibited the best performance with a cyclohexene selectivity and yield of 75.5% and 63.6%, respectively, at the benzene conversion of 84.3% in the third run. Moreover, the benzene conversion and cyclohexene selectivity were stable above 75% and cyclohexene yields were above 58% in fourth run.

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Effect of Resorcinol Formaldehyde Resin Gel on the Preparation of Co/SiO2 Catalysts for Fischer-Tropsch Synthesis CHEN Liang, SHEN Jian-Yi 2012, 33 (4):  621-628.  DOI: 10.1016/S1872-2067(11)60342-2 Abstract ( 2743 )   [Full Text(HTML)] () PDF (635KB) ( 785 )   Highly loaded Co/SiO2 catalysts were prepared by the co-precipitation method with resorcinol formaldehyde resin gel (RFG). Most RFG was decomposed during the drying process at 393 K, and little carbon was remained in the catalysts. However, the presence of RFG during the precipitation played the important roles in increasing the pore sizes of catalysts and the reducibility and dispersion of supported cobalt, leading to the more surface active cobalt sites and large pores of the catalysts and therefore the higher activity for the Fischer-Tropsch reactions to produce heavy hydrocarbons. The catalyst 80%Co/SiO2-C thus prepared was as active and selective as the 80%Co-8%ZrO2/SiO2 (an excellent catalyst reported previously) for the synthesis of heavy hydrocarbons from syngas.

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Synthesis, Characterization, and Nitrogen Concentration Depended Visible-Light Photoactivity of Nitrogen-Doped TiO2 Nanosheets with Dominant (001) Facets WANG Wei, LU Chun-Hua, SU Ming-Xing, NI Ya-Ru, XU Zhong-Zi 2012, 33 (4):  629-636.  DOI: 10.1016/S1872-2067(11)60348-3 Abstract ( 3141 )   [Full Text(HTML)] () PDF (617KB) ( 1057 )   Anatase TiO2 nanosheets with dominant (001) facets were prepared by a simple hydrothermal method. Nitrogen-doped TiO2 nanosheets (TiO2-N) with different nitrogen concentration were successfully synthesized by annealing TiO2 nanosheets in NH3 atmosphere with different NH3 flow rate at 400 °C for 3 h. The morphology, nanostructures, and properties of TiO2-N were characterized by X-ray diffraction, field emission scanning electron microscopy, high resolution transmission electron microscopy, ultraviolet-visible diffuse reflection spectroscopy, X-ray photoelectron spectroscopy, and photoluminescence. The effects of NH3 flow rate on the nanostructures, properties, and visible-light photoactivity in the degradation of rhodamine B (RhB) aqueous solution under visible light (λ > 400 nm) irradiation of the prepared photocatalysts were investigated. Among all the prepared photocatalysts including nitrogen modified P25 (Degussa), TiO2-N prepared with a NH3 flow rate of 40 ml/min gave the highest visible-light photoactivity because of the dominant (001) facets, visible light responsibility, the slowest photogenerated electron (e–) and hole (h+) pairs recombination rate, and the highest hydroxyl radicle (•OH) generation ability. Based on these experiments and analysis, the mechanisms of how the nitrogen concentration affects the visible-light photoactivity of TiO2-N were proposed.

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Characterization and Catalytic Activity of CeO2-Ni/Mo/SBA-15 Catalysts for Carbon Dioxide Reforming of Methane HUANG Jian, MA Ren-Xiong, GAO Zhi-Hua, SHEN Chao-Feng, HUANG Wei 2012, 33 (4):  637-644.  DOI: 10.1016/S1872-2067(11)60347-1 Abstract ( 2767 )   [Full Text(HTML)] () PDF (559KB) ( 1061 )   A Ni/Mo/SBA-15 catalyst was modified with CeO2 and compared with the unmodified catalyst. The catalysts were characterized by N2 adsorption, CO2 temperature-programmed desorption, H2 temperature-programmed reduction, Fourier transform infrared spectrometer, X-ray diffraction, scanning electron microscopy, and X-ray photoelectron spectroscopy. Both the Ni/Mo/SBA-15 and CeO2/Ni/Mo/SBA-15 catalysts gave good catalytic activities at atmospheric pressure. The CeO2 impregnated Ni/Mo/SBA-15 catalyst exhibited excellent stability at 800 ºC for 100 h on stream, and after the reaction, carbon deposits were not formed on the catalyst. The Ni/Mo/SBA-15 and CeO2/Ni/Mo/SBA-15 catalysts had a regular hexagonal mesoporous structure. The nickel species and the Ce-Mo oxide components were all in the SBA-15 mesopores. This prevented carbon deposition and sintering of the nickel species in the CeO2/Ni/Mo/SBA-15 catalyst.

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Microwave-Assisted Polyol-Synthesis of CoNi Nanomaterials GUO Xiao-Hui, LI Yong, LIU Qi-Ying, SHEN Wen-Jie 2012, 33 (4):  645-650.  DOI: 10.1016/S1872-2067(11)60350-1 Abstract ( 2819 )   [Full Text(HTML)] () PDF (1408KB) ( 1020 )   Co0.8Ni0.2 nano-urchins and nanowires were fabricated by microwave-assisted polyol-synthesis. Their structural evolution was monitored by powder X-ray diffraction and transmission electron microscopy measurements. The nucleation and growth rates of the crystals in their formation mechanism were discussed. Their catalytic activity for glycerol hydrogenolysis depended on their anisotropic shape and particle size.

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Fe3O4@PS@PAMAM-Ag Magnetic Nanocatalysts and Their Recoverable Catalytic Ability DANG Gao-Fei, SHI Yan, FU Zhi-Feng, YANG Wan-Tai 2012, 33 (4):  651-658.  DOI: 10.1016/S1872-2067(11)60369-0 Abstract ( 2836 )   [Full Text(HTML)] () PDF (583KB) ( 1026 )   Magnetic supports were prepared by coating Fe3O4 nanoparticles with polystyrene (PS). The target nanocomposites were formed by growing polyamidoamine (PAMAM) dendrimers on the magnetic polymer supports with carboxylic groups and then silver nanoparticles were embedded into the PAMAM dendrimer shell. In this way recoverable Fe3O4@PS@PAMAM-Ag nanocomposites were successfully prepared. The magnetic nanocatalysts were characterized by Fourier transform infrared spectra, scanning electron microscopy,?inductively coupled plasma, and X-ray photoelectron spectroscopy. The results demonstrated that the PAMAM dendrimer shell immobilized on the magnetic supports was beneficial for dispersion and stabilization of the silver nanoparticles. The silver content of the Fe3O4@PS@PAMAM(G7)-Ag nanoparticles was 1.64 wt%. The catalytic activity of the Fe3O4@PS@PAMAM-Ag nanocomposites was proved using the reduction of 4-nitrophenol as a model catalytic reaction. The nanocomposites could be readily separated by magnetic separation and reused for the next reduction with high efficiency. The catalytic activity remained completely even after the nanocatalyst had been recycled six times.

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Ammonium Dihydrogen Phosphate Catalyst for One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones Reza TAYEBEE, Behrooz MALEKI, Malihe GHADAMGAHI 2012, 33 (4):  659-665.  DOI: 10.1016/S1872-2067(11)60355-0 Abstract ( 2426 )   [Full Text(HTML)] () PDF (346KB) ( 1270 )   A one-pot three component Biginelli condensation of different substituted aromatic and aliphatic aldehydes with ethyl acetoacetate and urea to the respective 3,4-dihydropyrimidin-2-(1H)-ones under solvent-free conditions that is simple, effective, and environmentally friendly was shown. Ammonium dihydrogen phosphate (NH4H2PO4) was used as a non-toxic, inexpensive, and easily available catalyst. The facile reaction condition and simple isolation and purification procedures of this method make it a good option for the synthesis of dihydropyrimidinones.

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2-Pyrrolidinecarboxylic Acid Ionic Liquid Catalyzed Knoevenagel Condensation SONG Hong-Bing, YU Ying-Hao, CHEN Xue-Wei, LI Xue-Hui, XI Hong-Xia 2012, 33 (4):  666-669.  DOI: 10.1016/S1872-2067(11)60364-1 Abstract ( 2889 )   [Full Text(HTML)] () PDF (471KB) ( 908 )   The pyrrolidinecarboxylic functionalized ionic liquid, 1-butyl-3-methylimidazolium-(S)-2-pyrrolidinecarboxylic acid salt ([bmim][Pro]), was prepared using an improved procedure. α,β-Unsaturated carbonyl compounds were selectively synthesized and high yields (88%–97%) were obtained at room temperature in aqueous media when [bmim][Pro] was used as the catalyst for the Knoevenagel reaction between a methylene compound and an aldehyde or ketone. [bmim][Pro] was reused six times without loss of catalytic activity. The catalytic mechanism is briefly discussed.

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One-Step Cyclohexane Nitrosation to ε-Caprolactam over Metal Substituted AlPO-5 HAO Fang, ZHONG Jun, LIU Ping-Le, YOU Kui-Yi, WEI Chao, LUO He-An 2012, 33 (4):  670-676.  DOI: 10.1016/S1872-2067(11)60354-9 Abstract ( 2690 )   [Full Text(HTML)] () PDF (590KB) ( 869 )   Crystalline AlPO-5, SAPO-5, and metal substituted AlPO-5 (MeAlPOs) were prepared by the hydrothermal method and characterized by X-ray diffraction, N2 adsorption-desorption, scanning electron microscopy, particle size distribution, inductively coupled plasma (ICP) spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, NH3 temperature-programmed desorption (TPD), H2 temperature-programmed reduction, and thermogravimetric-differential thermogravimetric (TG-DTG) analysis. All the samples crystallized with the AFI structure. TPD profiles showed that stronger Brønsted acid sites appeared and the number of Lewis acid sites increased when Si or a metal was introduced into the framework of AlPO-5. ICP, FT-IR spectra, and TG-DTG curves confirmed that Si or the metals were incorporated into the framework of the AlPO-5. The catalytic properties of the samples in cyclohexane nitrosation to ε-caprolactam were studied. SAPO-5 with a larger BET surface area, more Lewis acid sites, and stronger Brønsted acid sites gave better activity and selectivity than AlPO-5. Among the MeAlPOs, CrAPO-5 with the larger BET surface area, more Lewis acid sites, and stronger Brønsted acid sites gave the better result with a conversion of 8.16% and ε-caprolactam selectivity of 68.17%.

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SiO2-NaHSO4 as an Efficient Reusable Heterogeneous Catalyst for the One-Pot Three-Component Synthesis of Octahydro-quinazolin-2,5-diones in Water Sadeq Hamood Saleh AZZAM, Aisha SIDDEKHA, Aatika NIZAM, Mohamed Afzal PASHA 2012, 33 (4):  677-680.  DOI: 10.1016/S1872-2067(11)60366-5 Abstract ( 2677 )   [Full Text(HTML)] () PDF (317KB) ( 1541 )   An environmentally benign method for the synthesis of octahydro-quinazolin-2,5-diones by the reaction of aromatic aldehydes, dimedone, and urea in the presence of SiO2-NaHSO4 is reported. SiO2-NaHSO4 acts as an efficient, mild, and recyclable heterogeneous catalyst to give excellent yields within a short reaction time in water at 60–80 °C.

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Efficient Synthesis of (R)-2-Chloro-1-(3-chlorophenyl)ethanol by Permeabilized Whole-Cells of Candida ontarioensis NI Ye, ZHANG Bei-Hua, SUN Zhi-Hao 2012, 33 (4):  681-687.  DOI: 10.1016/S1872-2067(11)60363-X Abstract ( 2609 )   [Full Text(HTML)] () PDF (461KB) ( 948 )   (R)-2-Chloro-1-(3-chlorophenyl)ethanol is a key pharmaceutical intermediate in the synthesis of β3-adrenoceptor receptor (β3-AR) agonists. The asymmetric reduction of 2-chloro-1-(3-chlorophenyl)ethanone to (R)-2-chloro-1-(3-chlorophenyl)ethanol catalyzed by resting cells of Candida ontarioensis was studied. At a substrate concentration of 10 g/L, the microbial cells showed excellent catalytic activity under the optimum reaction conditions, giving the product in 99.9% ee and 99.0% yield. After cetyltrimethylammonium bromide-pretreatment, the activity of permeabilized Candida ontarioensis cells was increased by more than 2-fold and the product could be produced over the significantly shortened reaction period of 24 h in 99.9% ee and 97.5% yield at a substrate concentration of 30 g/L. This work provides a practical approach for the efficient preparation of the important chiral intermediate (R)-2-chloro-1-(3-chlorophenyl)ethanol.

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A Zeolite Imidazolate Framework ZIF-8 Catalyst for Friedel-Crafts Acylation Lien T. L. NGUYEN, Ky K. A. LE, Nam T. S. PHAN* 2012, 33 (4):  688-696.  DOI: 10.1016/S1872-2067(11)60368-9 Abstract ( 3199 )   [Full Text(HTML)] () PDF (553KB) ( 2740 )   A zeolite imidazolate framework, ZIF-8, was synthesized and characterized by dynamic laser light scattering, X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared, atomic absorption spectrophotometry, and nitrogen adsorption measurements. The ZIF-8 was highly crystalline and porous with a surface area of over 1600 m2/g. Friedel-Crafts acylation of anisole and benzoyl chloride proceeded well in the presence of ZIF-8 (2–6 mol%) without the need for an inert atmosphere. The reaction afforded a selectivity of 93%–95% to the p-isomer. The solid catalyst can be separated from the reaction mixture by simple centrifugation and reused without significant degradation in catalytic activity. There was no leaching of active acid species into the reaction solution.

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Effect of Hydrohalogenation of PtRe/H-ZSM-5 for Cyclohexene Conversion Sameh M. K. ABOUL-FOTOUH, Noha A. K. ABOUL-GHEIT 2012, 33 (4):  697-705.  DOI: 10.1016/S1872-2067(11)60372-0 Abstract ( 2696 )   [Full Text(HTML)] () PDF (346KB) ( 1041 )   Extended use of supported Pt catalysts causes thermal migration of Pt particles to form large agglomerates, thus decreasing the catalytic activity. The combination of Pt with Re protects Pt against migration. In addition, Cl- injection into the reactor assists Pt particles redispersion to prolong catalyst life. In this work, a PtRe/H-ZSM-5 catalyst was treated with either HCl or HF to investigate their role in activating or deactivating the catalyst. The conversion exceeded 90% in the whole temperature range with the PtRe/H-ZSM-5(HCl) catalyst, and its activity for the direct isomerization of cyclohexene to methylcyclopentenes (MCPEs) was the lowest but the activity for the hydrogenation of the MCPEs to methylcyclopentane was the highest. The reactivities of MCPEs and cyclohexadienes on the catalysts were similar because both are dehydrogenation reactions. Benzene production was significantly higher on the hydrochlorinated catalyst than on the other catalysts, and its hydrocracking activity was the lowest, which is a good characteristic for processing catalysts where cracking is undesired.

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Sulfonated Carbon Catalyzed Biginelli Reaction for One-Pot Synthesis of 3,4-Dihydropyrimidin-2(1H)-ones and -thiones Maryam MOGHADDAS, Abolghasem DAVOODNIA, Majid M. HERAVI, Niloofar TAVAKOLI-HOSEINI 2012, 33 (4):  706-710.  DOI: 10.1016/S1872-2067(11)60377-X Abstract ( 2826 )   [Full Text(HTML)] () PDF (341KB) ( 1240 )   A sulfonated carbon material was shown to be a highly efficient, eco-friendly, and recyclable solid acid catalyst for the Biginelli reaction of β-ketoester, aldehyde, and urea or thiourea under solvent-free conditions. It gave 3,4-dihydropyrimidin-2(1H)-ones and -thiones in good to excellent yields. This method has the advantages of a simple procedure with easy work-up, short reaction time, and high yields. The catalyst can be recycled after a simple work-up and was reused four times without substantial reduction in activity.

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Synthesis of Mo-HMS and Its Catalytic Performance in Liquid Epoxidation of Propylene MIAO Yong-Xia, YANG Xin-Li, GUO Li-Hong 2012, 33 (4):  711-716.  DOI: 10.3724/SP.J.1088.2012.11031 Abstract ( 2634 )   [Full Text(HTML)] () PDF (445KB) ( 904 )   Mo-HMS was synthesized by a one-step hydrothermal method. Its structure and surface molybdenum species were characterized by X-ray diffraction, N2 adsorption-desorption, transmission electron microscopy, laser-Raman spectroscopy, and UV-Vis spectroscopy. The results show that introducing molybdenum species into HMS does not destroy the structure of HMS zeolite. There are three molybdenum species such as the isolated molybdenum species, polymolybdate species, and little crystalline MoO3 existing in the HMS support. Compared with impregnated MoO3/HMS and sol-gel MoO3/SiO2, the one-step method can lead to the decrease of crystalline MoO3 content by 39% and 61%, respectively. In the epoxidation of propylene with cumene hydroperoxide, the catalytic performance of Mo-HMS is better than that of MoO3/HMS and MoO3/SiO2, which is due to the higher dispersion of molybdenum species in Mo-HMS.

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Heterogeneous Bimetallic Pt-Sn/γ-Al2O3 Catalyzed N-Alkylation of Amines: Efficient Synthesis of Secondary and Tertiary Amines HE Wei, HE Song-Bo, SUN Cheng-Lin, WU Kai-Kai, WANG Lian-Di, YU Zheng-Kun 2012, 33 (4):  717-722.  DOI: 10.3724/SP.J.1088.2012.11105 Abstract ( 3148 )   [Full Text(HTML)] () PDF (898KB) ( 797 )   N-Alkylation of amines with alcohols through a borrowing hydrogen strategy is a green route to amines. Heterogeneous bimetallic Pt-Sn/γ-Al2O3 catalyzed the reactions of primary (secondary) amines with alcohols in the absence of external hydrogen source, efficiently affording secondary (tertiary) amines with water and a small amount of imines as the by-products. Various functional groups in the substrates were tolerated in the catalytic system. The Pt-Sn/γ-Al2O3 catalyst was easily recycled, suggesting its potential application in the production of secondary and tertiary amines.

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Ammoximation of Citronellal with H2O2 Catalyzed by TS-1 ZHANG Shuo, DENG Xiu-Juan, SHEN Lu, LIU Yue-Ming 2012, 33 (4):  723-729.  DOI: 10.3724/SP.J.1088.2012.11019 Abstract ( 2579 )   [Full Text(HTML)] () PDF (631KB) ( 926 )   The TS-1/H2O2 system has excellent catalytic performance in citronellal ammoximation to citronellal oxime. The effects of various reaction parameters on the catalytic properties of TS-1 were studied in detail. Under the optimized reaction conditions, citronellal conversion and citronellal oxime selectivity are over 99.9% and 99.2%, respectively. We found that there is also aldol condensation, which is competitive with ammoximation. Moreover, the epoxidation and ammoximation of citronellal catalyzed by TS-1 are also competitive reactions. The side reactions can be restrained efficiently by adjusting NH3 amount in reaction system.

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Synthesis of Formic Acid from CO2 Catalyzed by Formate Dehydrogenase Immobilized on Hollow Fiber Membrane LIU Wen-Fang, HOU Ben-Xiang, HOU Yan-Hui, ZHAO Zhi-Ping 2012, 33 (4):  730-735.  DOI: 10.3724/SP.J.1088.2012.11024 Abstract ( 2905 )   [Full Text(HTML)] () PDF (568KB) ( 1328 )   Formate dehydrogenase (FDH) was covalently attached to surface-modified polyethylene (PE) hollow fiber membrane. The effects of inlet way of CO2, pH value, the type of buffer solution, and the concentration of the reduced coenzyme nicotinamide adenine dinucleotide (NADH) on the synthesis of formic acid from CO2 were investigated. The catalytic performance of PE-supported FDH and its reusability were studied. The results showed that the CO2 bubbling method was superior to pressing method. Phosphate buffer was more favorable to the formation of formic acid than Tris-HCl and triethanolamine-HCl buffer. Immobilized FDH was less sensitive to pH than free FDH, and the optimum pH value was 6.0 for both systems. With the increase of NADH concentration, the initial reaction rate ascended while the yield tended to decrease. Enzyme activity reached 0.246 and 0.138 mmol/(L·h), respectively, for free and immobilized FDH when using 100 mmol/L of NADH. The stability was greatly improved after immobilization. The activity of PE-attached FDH only decreased by 4% while that of free enzyme dropped to 50% of initial activity after stored in phosphate buffer at 4 °C for two weeks. Furthermore, immobilized FDH exhibited outstanding reusability, which almost kept original activity after undergoing 10 cycles.

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Synthesis of Dimethyl Carbonate from Oxidative Carbonylation of Methanol Catalyzed by Cu(phen)Cl2 DU Zhi-Ping, ZHOU Bin, HUANG Li-Ming, HUANG Chen, WU Yuan-Xin, WANG Cun-Wen, SUN Wei 2012, 33 (4):  736-742.  DOI: 10.3724/SP.J.1088.2012.11121 Abstract ( 2959 )   [Full Text(HTML)] () PDF (543KB) ( 827 )   The copper coordination compound Cu(phen)Cl2 was prepared by the reaction of 1,10-phenanthroline with cupric chloride in the mixed solution of methanol and ethanol and was characterized by infrared spectroscopy, thermogravimetric analysis, and temperature-programmed reduction. Their catalytic performance for the oxidative carbonylation of methanol to dimethyl carbonate (DMC) was investigated. The results showed that Cu(phen)Cl2 had the high thermal stability and exhibited the high catalytic performance due to the effect of the σ-π coordination bond between phen and Cu(II). The turnover number (TON) could reach 51.5 mol of DMC per mol of Cu, under the conditions of reaction temperature 150 °C, total pressure 4.0 MPa, p(CO)/p(O2) = 19 (below the explosion limit of CO) and the catalyst concentration in methanol 0.011 mol/L. It was also found that there was an induction period at the early reaction stage, and the change of TON was the “M” type with the increase of temperature. Further, a novel reaction mechanism was suggested.